Performance Analysis Of Induction Motors With Rotor Eccentricity Faults And Its Detection Technology

With the rapid development of the Chinese economy,people's demands for the electricity sources have also increased greatly.Meanwhile,as the most important power source in the industry and people's daily life,the motors specially the induction motor play a significant role in the country.So the stability of the long-term operation of the induction motor is an important thing for the people's life level,development of the economy and the security of the country.Hence,it is becoming more and more crucial to study the performance of the machine under fault circumstance and conduct research on the fault diagnose aiming for the stability problem of the machine.This paper mainly takes the large and middle-small induction machine for examples and focuses on the rotor eccentricity fault especially.Then,discuss the effects on the air-gap flux density with different different eccentricity types.The performance of the machine will be further studied due to the eccentricity faults.A new kind online diagnose technology for the eccentricity will also be proposed in the final.This paper mainly focuses on the following aspects:1.Aimed at the rotor eccentricity fault in middle-small induction machine,mainly focus on the distortion of the air-gap flux density in mixed rotor eccentricity condition.Due to the particularity of the air-gap flux density,2D Fourier analysis has been proposed to extract the amplitude,order and frequency of the harmonics.Then the electromagnetic force can be figured out.2.Aimed at the large induction machine,specially the large the submersible motor,take the rotor deflection and gravity into consideration.Mainly concentrate on the calculation of the unbalanced magnetic pull(UMP)under curved dynaminc eccentricity.According to the numerical analysis result,the UMP at different position along the axial can be predicted.3.Analyze the iron loss distributions under static eccentricity and dynamic eccentricity respectively.A new online noninvasive method has been proposed to detect the rotor eccentricity fault,based on the different iron loss distributions in different eccentricity conditions.This paper mainly concentrates on the rotor eccentricity faults.Study the effects of different kinds of the eccentricity faults on the electromagnetic force,unbalanced magnetic pull and the iron loss.It lays a foundation for the study of the rotoreccentricity.